I put all my electrical and plumbing equipment on a single sheet of 5/8" plywood. It rests on two vertical 2x2's that are screwed into the wall. The sweated copper lines and connections are between the plywood and the wall out of sight.

In addition the electrical to the left on the board, there are two different water sources, filtered and unfiltered. The latter are used for washing prints, cleaning the sink, trays, etc. The former are used for mixing chemistry. Filtered lines are run through hot and cold darkroom filters I bought years ago. It's important that the hot water filter can stand the heat.

This took me months to complete while it sat upturned in our living room entryway. But it's handy, because when I leave this house, it leaves with me.

This darkroom board is connected to water through two hoses, and connected to electrical via a plug.